H<sub>3</sub>PO<sub>4</sub>的pK<sub>a1</sub>,pK<sub>a2</sub>,pK<sub>a3</sub>分别是2.12,7.20,12.40,当H<sub>3</sub>PO<sub>4</sub>溶液的pH=7.20时,溶液中的主要存在形式是()
A、H2PO4-和HPO42-
B、H2PO4-
C、HPO42-
D、HPO42-和PO43-
A、H2PO4-和HPO42-
B、H2PO4-
C、HPO42-
D、HPO42-和PO43-
A、CaCO<sub>3sub>+H<sub>3sub>PO<sub>4sub> B、Ca<sub>5sub>F(PO<sub>4sub>)<sub>3sub>+H<sub>2sub>SO<sub>4sub> C、CaF<sub>2sub>+H<sub>3sub>PO<sub>4sub> D、CaSO<sub>4sub>+H<sub>3sub>PO<sub>4sub>
A、H<sub>2sub>PO<sub>4sub> B、H<sub>2sub>PO<sub>3sub> C、H<sub>3sub>PO<sub>4sub> D、HPO<sub>3sub>
A、H<sub>3sub>PO<sub>4sub> B、H<sub>3sub>PO<sub>3sub> C、H<sub>3sub>PO<sub>2sub> D、H<sub>4sub>P<sub>2sub>O<sub>7sub> E、(HPO<sub>3sub>)n
A、[H<sub>2sub>PO<sub>4sub>-]>[HPO<sub>4sub>2-] B、[HPO<sub>4sub>2-]>[H<sub>2sub>PO<sub>4sub>-] C、[H<sub>2sub>PO<sub>4sub>-]<[HPO<sub>4sub>2-] D、[PO<sub>4sub>3-]>[HPO<sub>4sub>2-]
A、H<sub>2sub>C<sub>2sub>O<sub>4sub> B、稀H<sub>2sub>SO<sub>4sub> C、H<sub>2sub>CO<sub>3sub> D、H<sub>3sub>PO<sub>4sub>
A、H<sub>3sub>PO<sub>4sub> B、H<sub>2sub>PO-<sub>4sub> C、HPO2-<sub>4sub> D、PO3-<sub>4sub>
A、H<sub>2sub>C<sub>2sub>O<sub>4sub> B、稀H<sub>2sub>SO<sub>4sub> C、Na<sub>2sub>CO<sub>3sub> D、H<sub>3sub>PO<sub>4sub>